These questions are somewhat of a topic hijack, so a forum moderator could probably split them out into it's own discussion
Nocks are used on some kites, they look much like the nock on an arrow. They have a U-shaped edge that a tight cord is placed inside. When placed under tension the cord can slip back out of the nock to release the spar.
These kites use an end cap. The cord is threaded through the cap and left in place indefinitely. The end cap is slipped on or off the spar when you set up or break down the kite.
More on the rods below...
A split spar is broken, even if it hasn't completely failed. You can tape it, epoxy it, or otherwise try to get some more life out of it, but that is playing with fire. Sometime soon you'll hit a gust or a crash and the spar will fail completely. That will probably mean a sharp edge, and it can mean the broken spar will rip through the fabric. Better to replace the spar now rather than wait for a catastrophic failure that risks even more damage.
The good news is you don't need to ship away for them. A store called A Wind of Change moved from Las Vegas to SLC a few years ago. Although they transitioned the business from a brick-and-mortar shop to an online shop, they have a bunch of good stuff in stock at their home. Email or call, explain what you're interested in buying, that you live in Salt Lake, and that you'd like to look at the parts if they can arrange a time. Most likely either Kent or Daelyn will arrange for a visit if you know what you're planning on buying. They're located in North Salt Lake by the I-215 curve.
I'm sure they have the official revolution rods as well as SkyShark rods in stock. They could show you the difference (and similarities), and sell you whatever parts you need for your kite bag. If you don't have one, I'm sure they could sell you a quality kite bag, too. ;-)